DHT22 temperatuur en vochtigheid sensor

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Pin Identification and Configuration

No:Pin NameDescription
For DHT22 Sensor
1VccPower supply 3.5V to 5.5V
2DataOutputs both Temperature and Humidity through serial Data
3NCNo Connection and hence not used
4GroundConnected to the ground of the circuit
For DHT22 Module
1VccPower supply 3.5V to 5.5V
2DataOutputs both Temperature and Humidity through serial Data
3GroundConnected to the ground of the circuit

DHT22 Specifications

  • Operating Voltage: 3.5V to 5.5V
  • Operating current: 0.3mA (measuring) 60uA (standby)
  • Output: Serial data
  • Temperature Range: -40°C to 80°C
  • Humidity Range: 0% to 100%
  • Resolution: Temperature and Humidity both are 16-bit
  • Accuracy: ±0.5°C and ±1%

How to use DHT22 Sensor

The DHT22 Sensor is factory calibrated and outputs serial data and hence it is highly easy to set it up. The connection diagram for this sensor is shown below.

DHT22 Microcontroller Interfacing Circuit Diagram

As you can see the data pin is connected to an I/O pin of the MCU and a 5K pull up resistor is used. This data pin outputs the value of both temperature and humidity as serial data. If you are trying to interface DHT22 with Arduino Uno then there are ready made libraries for it which will give you a quick start.

If you are trying to interface it with some other MCU then the datasheet given below will come in handy. The output given out by the data pin will be in the order of 8bit humidity integer data + 8bit the Humidity decimal data +8 bit temperature integer data + 8bit fractional temperature data +8 bit parity bit. To request the DHT11 module to send these data the I/O pin has to be momentarily made low and then held high as shown in the timing diagram below.

DHT22 Timing Diagram

The duration of each host signal is explained in the datasheet, with neat steps and illustrative timing diagrams



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